| Abstract |
A critical analysis of alkali-activated cements as sustainable materials demonstrates their advantages compared to traditional Portland cements. It also makes it possible to identify the main drivers of alkaline activation in the production of cements for mortars and concretes used in repairing building construction. These materials are effective for repairing, retrofitting, and rehabilitation of damaged structures (pavement, bridge decks, tunnel structures, highways, airport runways, berths, piers, coast-protecting structures, dams, etc.). Technical drivers are based on cements with high physical and mechanical properties and durability, due to a highly effective hydrate composition in cement stone. This has benefits due to a lack of free Ca(OH)2, ettringite, and highly basic calcium silicates in the presence of low basic calcium silicates and zeolite-like hydration products. Environmental drivers are associated with the reduction or elimination of non-renewable raw materials from Portland cement clinker, and the high clinker efficiency resulting from the activation and application of industrial by-products and wastes, as well as seawater. Commercial drivers are justified by low specific energy consumption in cement production, reductions in costs for exceeding CO2, SO2, and mercury emission quotas, and a low cost of raw materials, due to the use of a high proportion of by-products, such as fuel ashes, metallurgical slags, red mud, silica, ceramic powder, etc. |